OPTICAL STUDIES OF ZNXCD(1-X)SE SEMICONDUCTING TERNARY FILMS GROWN

ZnxCd1-xSe policrystalline thin films grown by closed Spaced vapor Tra nsport (CSVT) were studied by X-Ray diffraction, optical absorption sp ectroscopy, scanning electron microscopy, Raman spectroscopy and photo luminescence. Our studies show that the structure is cubic (zinc-blend ) for x greater than or equal to 0.7, hexagonal (wurtzite) for x less than or equal to 0.4 and for the intermediate range 0.4 < x < 0.7 both phases coexist. Raman spectroscopy confirms these results and in addi tion an intermediate vibrational behavior is observed in which impurit y modes of Cd in ZnSe and Zn in CdSe evolve along with LO and TO phono ns throughout the mixture.